title: Signal amplification for DNA detection based on the HRP-functionalized Fe3O4 nanoparticles.
abstract: An electrochemical approach for the sensitive detection of sequence-specific DNA has been developed. Horseradish peroxidase (HRP) assembled on the Fe(3)O(4) nanoparticles (NPs) were utilized as signal amplification sources. High-content HRP was adsorbed on the Fe(3)O(4) NPs via layer-by-layer (LbL) technique to prepare HRP-functionalized Fe(3)O(4) NPs. Signal probe and diluting probe were then immobilized on the HRP-functionalized Fe(3)O(4) NPs through the bridge of Au NPs. Thereafter, the resulting DNA-Au-HRP-Fe(3)O(4) (DAHF) bioconjugates were successfully anchored to the gold nanofilm (GNF) modified electrode surface for the construction of sandwich-type electrochemical DNA biosensor. The electrochemical behaviors of the prepared biosensor had been investigated by the cyclic voltammetry (CV), chronoamperometry (i-t), and electrochemical impedance spectroscopy (EIS). Under optimal conditions, the proposed strategy could detect the target DNA down to the level of 0.7 fmol with a dynamic range spanning 4 orders of magnitude and exhibited excellent discrimination to two-base mismatched DNA and non-complementary DNA sequences.
authors.affiliation: The Key Lab of Analytical Chemistry for Life Science (MOE), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Xiao-Ya
authors.initials: XY
authors.lastname: Dong
authors.forename: Xiao-Na
authors.initials: XN
authors.lastname: Mi
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.forename: Jing-Juan
authors.initials: JJ
authors.lastname: Xu
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Chen
mesh_terms: D004247:DNA / Q000032:analysis*; D004563:Electrochemistry; D005290:Ferric Compounds / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry*; D053768:Metal Nanoparticles
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D004247:DNA; D006735:Horseradish Peroxidase